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On Ducking Challenges to Naturalism

The Stone is a forum for contemporary philosophers and other thinkers on issues both timely and timeless.

In response to the question posed in my previous essay in The Stone — “What is naturalism?” — Alex Rosenberg defines it as “the philosophical theory that treats science as our most reliable source of knowledge and scientific method as the most effective route to knowledge.” His post, “Why I Am a Naturalist,” nicely exemplifies one of my main complaints, by leaving it unclear what he means by “science” or “scientific method,” even though it is crucial for what he is committing himself to as a “naturalist.” Still, there are clues. He describes “the test of knowledge that scientific findings attain” as “experimental/observational methods,” which suggests that theorems of mathematics would not count as scientific findings. The impression is confirmed by Professor Rosenberg’s phrase “mathematicians and scientists,” as though he doesn’t see mathematicians as scientists. That’s bad news for his naturalism, for mathematical proof is just as effective a route to knowledge as experimental/observational methods. Of course, since the natural sciences depend on mathematics, Rosenberg desires to find a place for it — but admits that he doesn’t know how.

Can physics do better than history at getting right what happened at Gettysburg?

In just the way noted in my post, Professor Rosenberg’s defense of naturalism trades on ambiguities. Interpreted one way, some naturalist claims are boring truths; interpreted another way, they are obvious falsehoods. Rightly noting the successes of physics, he says “We should be confident that it will do better than any other approach at getting things right.” What things? If he means questions of physics, what reasonable person denies that physics will do better than any other approach at answering those questions? But if he means all questions, why should we be confident that physics will do better than history at getting right what happened at Gettysburg?

I raised history and literary theory as test cases. According to Professor Rosenberg, naturalism treats literary criticism as fun, but not as knowledge. Does he really not know whether Mr. Collins is the hero of “Pride and Prejudice?” Every normal reader has that sort of elementary literary critical knowledge. Those who know far more about the historical context in which literary works were produced, read them many times with unusual attention, carefully analyze their structure, and so on, naturally have far more knowledge of those works than casual readers do, whatever the excesses of post-modernism.

As for history, Rosenberg conveniently avoids discussing it. He seems not to regard it as a science, but does not come out and say that there is no historical knowledge, or none worth having. It might suit some politicians for there to be no historical knowledge; the rest of us must hope that they don’t attain or retain power. It isn’t even clear how natural science could manage without historical knowledge, as R.G. Collingwood long ago pointed out, since knowledge of the results of past experiments and observations is itself historical.

For Professor Rosenberg, it may turn out that “reality contains only the kinds of things that hard science recognizes.” By “hard science” he seems to mean something like physics. He doesn’t explain how that could turn out. How could physics show that reality contains only the kinds of things that physics recognizes? It sounds embarrassingly like physics acting as judge and jury in its own case. That physics does not show that there is such a thing as a debt crisis does not mean that physics shows that there is no such thing as a debt crisis: physics simply does not address the question. That is no criticism of physics; it has other work to do. For it to turn out that reality contains only the kinds of things that hard science recognizes, where they exclude things like debt crises, it would have to turn out that a radically reductionist metaphysical theory is true. That in turn would require industrial-scale argument at a characteristically philosophical level of reasoning. But I doubt that Professor Rosenberg counts philosophy as hard science.

We can formulate the underlying worry as a sharp argument against the extreme naturalist claim that all truths are discoverable by hard science. If it is true that all truths are discoverable by hard science, then it is discoverable by hard science that all truths are discoverable by hard science. But it is not discoverable by hard science that all truths are discoverable by hard science. “Are all truths discoverable by hard science?” is not a question of hard science. Therefore the extreme naturalist claim is not true.

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Such problems pose far less threat to more moderate forms of naturalism, based on a broader conception of science that includes mathematics, history, much of philosophy, and the sensible parts of literary criticism, as well as the natural and social sciences. But we should not take for granted that reality contains only the kinds of things that science even in the broad sense recognizes. My caution comes not from any sympathy for mysterious kinds of cognition alien to science in the broad sense, but simply from the difficulty of establishing in any remotely scientific way that reality contains only the kinds of thing that we are capable of recognizing at all. In any case, Professor Rosenberg does not rest content with some moderate form of naturalism. He goes for something far more extreme, in the process lapsing into hard scientism.

Professor Rosenberg concludes: “What naturalists really fear is not becoming dogmatic or giving up the scientific spirit. It’s the threat that the science will end up showing that much of what we cherish as meaningful in human life is illusory.” But what people really fear is not always what most endangers them. Those most confident of being undogmatic and possessing the scientific spirit may thereby become all the less able to detect dogmatism and failures of the scientific spirit in themselves. If one tries to assess naturalism in a scientific spirit, one will want to get more precise than most self-labelled naturalists (and anti-naturalists) do about what hypothesis is under test. Nor will one dogmatically assume that, once a clear hypothesis is on the table, testing it will be just a matter for hard science. The evidence so far suggests otherwise.

Timothy Williamson is the Wykeham Professor of Logic at Oxford University, a Fellow of the British Academy and a Foreign Honorary Member of the American Academy of Arts and Sciences. He has been a visiting professor at M.I.T. and Princeton. His books include “Vagueness” (1994), “Knowledge and its Limits” (2000) and “The Philosophy of Philosophy” (2007).

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The Stone features the writing of contemporary philosophers and other thinkers on issues both timely and timeless. The series moderator is Simon Critchley. He teaches philosophy at The New School for Social Research in New York. To contact the editors of The Stone, send an e-mail to opinionator@nytimes.com. Please include “The Stone” in the subject field.